A man rides a bicycle holding a part of a mortar bomb at a checkpoint near Andriyivka village outside Slovyansk, eastern Ukraine, Saturday, May 17, 2014. Outside the strategic city of Slovyansk, which has been the key stronghold of the pro-Russian insurgents for more than a month now, the armed separatists installed a new check-point on the eastern approaches of the city blocking the major highway which links Kharkiv, the capital of the neighboring region, and the Russian city of Rostov-on-Don across the border. (AP Photo/Alexander Zemlianichenko)

Pro-Russian militants take their positions using an armored personnel carrier preparing to fight against Ukrainian government troops at a checkpoint blocking the major highway which links Kharkiv, outside Slovyansk, eastern Ukraine, Friday, May 16, 2014, with a Donetsk peoples republic flag atop. Outside the strategic city of Slovyansk, which has been the key stronghold of the pro-Russian insurgents for more than a month now, the armed separatists installed a new check-point on the eastern approaches of the city blocking the major highway which links Kharkiv, the capital of the neighboring region, and the Russian city of Rostov-on-Don across the border. (AP Photo/Alexander Zemlianichenko)

A masked pro-Russian militant stands behind the barricades at a checkpoint blocking the major highway which links Kharkiv, outside Slovyansk, eastern Ukraine, Saturday, May 17, 2014.. Outside the strategic city of Slovyansk, an insurgent stronghold for more than a month now, armed separatists installed a new checkpoint on the eastern approaches to the city, blocking a major highway that links Kharkiv, Ukraine's second-largest city, with the Russian city of Rostov-on-Don across the border. (AP Photo/Alexander Zemlianichenko)

KIEV, Ukraine - Lawmakers and officials from eastern Ukraine on Saturday poured criticism on the fledging central government, accusing it of ignoring legitimate grievances of the regions which have been overrun by pro-Russia militia fighting for independence.

One eastern leader said last weekend's unofficial referendum in favour of independence "expressed the will of the people."

The criticism came in the second round of European-brokered talks intended to resolve the country's worst crisis since the fall of the Soviet Union in 1991.

Ukraine's caretaker government came to power in February following the ouster of Kremlin-friendly President Viktor Yanukovych after months of protests in Kyiv. Moscow and many in Ukraine's east have accused the new government of intending to trample the rights of eastern Ukraine's Russian-speakers.

On Saturday, politicians from the east implored the government to believe that — apart from the pro-Russia gunmen — a large sector of the population had lost hope in the interim administration in Kyiv.

The second round of talks followed hours after sustained gunfire heard throughout the night near the eastern city of Slovyansk, the stronghold of pro-Russia fighters, after forces loyal to the Kyiv government moved in to protect a television tower.

Separatists in the Donetsk and Luhansk regions held hastily arranged referenda last weekend and declared independence following the vote, which went in favour of sovereignty.

The round-table talks in the eastern city of Kharkiv did not feature any of the insurgents, whom Kyiv describes as terrorists. The insurgents say they are willing to discuss only the withdrawal of Ukrainian troops and the recognition of the independence of the regions.

"The referendum doesn't have any legal consequences," said Valery Holenko, chairman of the Luhansk regional government. "But it has expressed the will of the people, which cannot be discounted. People genuinely went en masse to the referendum. This was a protest vote."

Holenko said the devolution of powers that the government is offering was no longer enough and that as a first step in appeasing eastern Ukrainians the government has to stop its "anti-terrorist operation" in the east.

Acting Prime Minister Arseniy Yatsenyuk, who was often busy with his iPad while some of the eastern lawmakers were making passionate speeches, called on the eastern leaders to resist the armed men and support the government's efforts to devolve powers to the regions.

"You have got in your home, in Luhansk and Donetsk, armed terrorists who are funded by Russians and those who fled Ukraine and want to seize our land," Yatsenyuk told the gathering.

"We're not going talk to robbers and terrorists. They will not be telling the Ukrainian people how to live in our country."

Yatsenyuk urged the eastern leaders to disarm the insurgents, "regain the power and start a political dialogue."

Reacting to calls to make Russian a second official language, Yatsenyuk said the government will support the equal status of Ukrainian and Russia in Russian-speaking regions but sees no need for other legal protection.

Reacting to the fighting overnight near Slovyansk, the Russian Foreign Ministry issued a statement condemning what it described as a sharp escalation of violence in eastern Ukraine, and accused Kyiv of using the talks as cover for military operations against its citizens.

The ministry said some people were wounded, but gave no specifics.

Debris from the shooting was visible Saturday morning, including a badly damaged train and craters caused by mortar bombs or other heavy artillery.

Government forces in recent weeks have achieved only limited results in quashing the self-styled Donetsk and Luhansk "people's republics," which declared independence for their regions following the contentious votes on independence.

Polls have shown, however, that a majority of eastern Ukrainians support a united country, although most are too fearful of the armed separatists to say so publicly.

As on Wednesday, Saturday's talks included officials, lawmakers, business people and religious leaders from across the country, but no representatives of the separatists from Donetsk and Luhansk.

Oleksandr Bandurka, a Communist party lawmaker and police general from central Ukraine, said that these negotiations make no sense because "we're not talking to those who oppose us. We cannot ignore them."

Ukraine's first president, Leonid Kravchuk, who is chairing the talks, angrily reacted that "no one in the world talks to killers and terrorists. Putin doesn't talk to terrorists."

Russia has pushed for the federalization of Ukraine, since that would allow Moscow to retain influence over areas in Ukraine dominated by Russian-speakers. Many in western Ukraine and in the capital favour closer ties to Europe and fear being pulled back into Moscow's orbit.

Volodymyr Groisman, acting prime minister in charge of the reforms to decentralize the government, countered the claims of some eastern lawmakers that only federalization — as proposed by Moscow — will bring peace to Ukraine.

"You were saying the unitary system of government is no longer effective?" Groisman said. "An inefficient government and dirty politics — this is what led to the fact that so many people in our country are poor."

Attempting to end the talks on a conciliatory note, Yatsenyuk quoted Ukrainian poet Taras Shevchenko and told the leaders from eastern Ukraine: "We are ready to embrace you and hope that you are too."

U.S. State Department spokesperson Jen Psaki rejected the "illegal actions" of un-elected pro-Russian separatists in eastern Ukraine who want the region to become part of Russia. But she said the U.S. supports the efforts by "elected and legitimate representatives" meeting in Kharkiv "to discuss constitutional and nonviolent approaches to resolving their differences."

"Any decisions made about Ukraine must be taken by those with lawful authority, representing the citizens of Ukraine as a whole, and not under threat of foreign military intervention," Psaki said.

The next round of talks is expected on Wednesday in the central city of Cherkasy.